Field of the Disclosure
The present disclosure relates to an organic light emitting diode display.
Discussion of the Related Art
Recently, various flat panel displays that are less bulky and lighter than cathode ray tubes (CRTs) are being developed. Examples of the flat panel displays include liquid crystal displays (LCDs), field emission displays (FEDs), plasma display panels (PDPs), organic light emitting diode displays (OLEDs), etc. Among these types of flat panel displays, the organic light emitting diode displays are self-luminous displays that emit light through excitation of organic compounds. In contrast to LCDs the organic light emitting diode displays work without a backlight; thus, organic light emitting diode displays can be lighter and thinner and made in a simplified process. Also, the organic light emitting diode displays are widely used because they can be manufactured at low temperatures, have a fast response time of 1 ms or less, and feature low power consumption, wide viewing angle, and high contrast.
An organic light emitting diode display comprises an organic light emitting diode that converts electrical energy into light energy. The organic light emitting diode comprises an anode, a cathode, and an organic emission layer situated between the anode and cathode. A hole is ejected from the anode, and an electron is ejected from the cathode. Once the hole from the anode and the electron from the cathode are injected into an organic emission layer EML, they form an exciton and this exciton releases its energy as light to emit light.
In such an organic light emitting diode display, each pixel comprises a switching thin film transistor and a driving thin film transistor, in order to apply a driving signal to the anode in a display area. The switching thin film transistor functions to select a pixel. The driving thin film transistor serves to drive the organic light emitting diode of the pixel selected by the switching thin film transistor.
In line with the rising demand for high resolutions needed for larger display sizes, pixel sizes are becoming smaller and smaller. One pixel is defined by the intersection of a gate line, a data line, and a common power supply line. In this pixel, a switching thin film transistor, a driving thin film transistor, a storage capacitor, and an organic light emitting diode are formed, or located. With this configuration, the thin film transistors and the above-mentioned lines can be integrated due to the smaller pixel size, so they are arranged very close to each other.
A parasitic capacitor is formed between the driving thin film transistor's gate electrode and a line adjacent to it, for example, a data line to which a data voltage is applied. In this instance, the gate voltage applied to the gate electrode of the driving thin film transistor changes due to a change in the data voltage applied to the data line. A change in the gate voltage due to interference from the data voltage leads to a change in the gate-source voltage Vgs of the driving thin film transistor. The user will perceive this as a vertical crosstalk. The vertical crosstalk degrades the display quality and reliability of the display device. Therefore, there is a need for an effort to solve this problem.